A. Field of the Invention
The present invention relates generally to a sensor assembly for automatic sinks, and, more particularly, to a sensor assembly having a flexibly mounted fiber optic proximity sensor. Such a sensor assembly may be used with any type of automatic sink or in other applications requiring an automatically controlled supply of water, chemical, etc. Preferably, however, such a sensor assembly is used with surgical scrub sinks.
B. Description of the Related Art
Automatic sinks permit a person to wash his or her hands without the need to turn on or off water supply faucets. Without such automatic sinks, a water supply may be left running or conversely require human skin contact for operation. The latter is a particular problem in surgical sinks where it is essential that the surgeon not touch any object which might be unsterile. Public restrooms are also another location where dangerous bacterial and fungal deposits on water supply faucets pose a potential health risk. This has lead to various approaches for controlling the on and off operation of faucets which do not require the user to physically touch a control knob for manipulating the faucet.
One approach, as disclosed in Rosa, U.S. Pat. No. 4,942,631, is the utilization of an infrared sensor above or in the sink itself for detecting the user's hands in the vicinity of the faucet. This approach suffers from the disadvantage that the faucet turns off when the user's hands are away from the immediate vicinity of the faucet, even though the washing operation is incomplete. This necessitates turning the faucet on again upon detection of the user's hands and results in an intermittent on-and-off action of the faucet.
Attempts to avoid the above problems resulted in various designs, such as changing the spread or focal length of the sensor to permit detection of the user's hands when they are not in the immediate vicinity of the faucet. Unfortunately, this caused detection of other objects in the sensor beam so that the faucet turned on even in the absence of the user.
Another approach, as illustrated in Paterson et al., U.S. Pat. No. 5,412,816, assigned to the assignee of the present invention, comprises fixedly mounting a short focus sensor to the drain pipe of a sink tub and a wall at the height of the user's legs for detecting the presence or absence of the user in the vicinity of the tub. The sensor operatively connects to a water supply on/off mechanism, turning on the faucet when the presence of the user is detected and turning off the faucet when the user is absent. Such an arrangement solves the disadvantages of the various approaches noted above. However, the arrangement prevents custom fitting of the sensor to a variety of sinks and adjustable positioning of the sensor due to its fixed mounting configuration.